1. Field of the Invention
The present invention is generally related to a siphon inhibiting device for a marine propulsion system and, more particularly, to a siphon inhibiting valve comprises an internally movable buoyant member which is constrained to cause one particular portion of the buoyant member to move into sealing association with an inlet portion of the device.
2. Description of the Prior Art
Those skilled in the art of marine propulsion systems are aware of many different types of engine cooling systems. Typically, a water pump is used to draw water from the body of water in which the marine propulsion system is operated. The water is then conducted through a series of passages and into thermal communication with various heat producing components, such as the engine and its exhaust manifolds. After being used to remove heat from the heat producing components, the water is then typically combined with an exhaust stream from the engine and conducted overboard, back into the body of water from which it was drawn.
U.S. Pat. No. 5,980,342, which issued to Logan et al on Nov. 9, 1999, discloses a flushing system for a marine propulsion engine. The flushing system provides a pair of check valves that are used in combination with each other. One of the check valves is attached to a hose located between the circulating pump and the thermostat housing of the engine. The other check valve is attached to a hose through which fresh water is provided. Both check valves prevent flow of water through them unless they are associated together in locking attachment. The check valve attached to the circulating pump hose of the engine directs a stream of water from the hose toward the circulating pump so that water can then flow through the circulating pump, the engine pump, the heads, the intake manifold, and the exhaust system of the engine to remove seawater residue from the internal passages and surfaces of the engine. It is not required that the engine be operated during the flushing operation.
U.S. Pat. No. 5,334,063, which issued to Inoue et al on Aug. 2, 1994, describes a cooling system for a marine propulsion engine. A number of embodiments of cooling systems for marine propulsion units are disclosed which have water cooled internal combustion engines in which the cooling jacket of the engine is at least partially positioned below the level of the water in which the water craft is operating. The described embodiments all permit draining of the engine cooling jacket when it is not being run. In some embodiments, the drain valve also controls the communication of the coolant from the body of water in which the water is operating with the engine cooling jacket. Various types of pumping arrangements are disclosed for pumping the bilge and automatic valve operation is also disclosed.
U.S. Pat. No. 6,004,175, which issued to McCoy on Dec. 21, 1999, discloses a flush valve which uses only one moving component. A ball is used to seal either a first or second inlet when the other inlet is used to cause water to flow through the valve. The valve allows fresh water to be introduced into a second inlet in order to remove residual and debris from the cooling system of the marine propulsion engine. When fresh water is introduced into a second inlet, the ball seals the first inlet and causes the fresh water to flow through the engine cooling system. When in normal use, water flows through the first inlet and seals the second inlet by causing the ball to move against a ball seat at the second inlet. Optionally, a stationary sealing device can be provided within the second inlet and a bypass channel can be provided to allow water to flow past the ball when the ball is moved against the ball seat at the first inlet. This minimal flow of water is provided to allow lubrication for the seawater pump impeller if the seawater pump is operated during the flushing operation in contradiction to recommended procedure.
U.S. Pat. No. 6,135,064, which issued to Logan et al on Oct. 24, 2000, discloses an improved drain system. The engine cooling system is provided with a manifold that is located below the lowest point of the cooling system of the engine. The manifold is connected to the cooling system of the engine, a water pump, a circulation pump, the exhaust manifolds of the engine, and a drain conduit through which all of the water can be drained from the engine.
The patents described above are hereby expressly incorporated by reference in the description of the present invention.
In certain types of marine propulsion systems, water can drain and thereby create a siphon effect that draws water from other components of the cooling system. When the engine is turned off, cooling water in the outboard drive drains downward to the water line of the body of water in which the boat is operated. This draining initiates a siphon effect which, in turn, draws cooling water from the heated engine in a reverse direction through the cooling circuit. The heated water from the engine then enters and remains in the fuel/water heat exchanger which, in most cases, is a coaxial heat exchanging device. The heated water in this fuel/water heat exchanger causes the liquid fuel to increase in temperature and, in certain cases, vaporize. When the operator of a marine vessel then tries to restart the engine, this partially vaporized fuel in the fuel/water heat exchanger is difficult to displace with the typical electric fuel pump that is normally used. As a result, vapor lock can be experienced.
It would therefore be significantly beneficial if an improved valve could be provided that prevents the siphon effect from draining the water from the cooling system soon after the pump is deactivated, while also avoiding any disadvantages that may have been experienced by users of known anti-siphon valves. It would be further beneficial if the siphon inhibiting means could also allow later draining of the cooling system.
A siphon inhibiting valve for a marine propulsion system, made in accordance with the preferred embodiment of the present invention, comprises a housing structure having an inlet port and an outlet port. A buoyant member is disposed for movement along the first axis within the housing structure. The buoyant member is inhibited from rotating about a second axis which is perpendicular to the first axis. A sealing surface of the buoyant member is movable into contact with the housing structure proximate the inlet port. In response to movement of the buoyant member toward the inlet port, and into contact with the housing structure, a seal inhibits a liquid from flowing in a reverse direction from the outlet port through the inlet port.
A guide member is disposed within the housing structure and has an opening formed therein which is shaped to receive the buoyant member in sliding relation. The housing structure comprises a first portion and a second portion which are attached together.
The buoyant member comprises a generally cylindrical portion and a portion which is a frustum of a cone. The sealing surface of the buoyant member can comprise an elastomeric insert attached to the buoyant member. Certain embodiments of the present invention further comprise a lip formed in the housing structure surrounding the inlet port, wherein the elastomeric member is shaped to form a seal with the lip when the buoyant member moves toward the inlet port and into contact with the housing structure. The elastomeric insert can be a ring that is shaped to be received in a slot formed in the buoyant member.
The housing structure is intended to be connected in fluid communication with the cooling system of a marine propulsion system, with the inlet port disposed upstream within the cooling system to receive cooling water from a body of water and an outlet port disposed downstream within the cooling system to conduct water to a cooling system of an engine of the marine propulsion system. The buoyant member can be rotatable about the first axis and the buoyant member can be at least partially hollow.
The buoyant member is provided with a generally blunt face at an end of the buoyant member most proximate the inlet port, whereby the buoyant member being inhibited from rotating about the second axis which is perpendicular to the first axis causes the generally blunt face to be maintained in a position facing the inlet port.